nobody or other service users on unix generally have password set to NP or some other special string that does not actually work as a password for the system. This in effect locks out standard auth on the user and only allows su - actions from root.
The second one as I read it means that DBI access is out of the question -- It either means that his script cant hold the auth keys (no auth at all) or that the auth should be in a form that is not usable in perl.